Plain English Summary

Background and study aims Children with small lower jaws and prominent upper front teeth represent about one third of the workload of British Orthodontists. The braces aim to reduce the prominence of the teeth by bringing the lower jaw forward to 'catch up' with the upper jaw. This treatment reduces the risk of damage to the upper teeth and improves the bite (eating) in some cases. The orthodontic brace used to correct the small lower jaw and prominent upper teeth is called a 'twinblock'. This brace has been in used for over 30 years and is used widely on growing children between around 10 1/2 and 15 years old. If an orthodontist was asked whether the twinblock works best on a 10.5 year old or a 15 year old they would be unsure of the correct answer. This is because there is no research to help with the decision. Therefore, this study has two groups, an earlier and a later group where the earlier group starts treatment straight away and the later group waits until they are 18 months older. The aim of the treatment is to assess how well the twinblock brace works comparing the earlier and later groups. We will measure jaw and tooth improvements and also self esteem and how patients feel about their teeth.

Who can participate?Boy or a girl, age 10.5 - 13.5 years. You can take part if you have a small lower jaw and top front teeth that 'stick out'. You will need to be happy to wear the brace.

What does the study involve?The treatment is with a twinblock brace. It is plastic two part top and bottom brace that clips over your teeth. You would wear the brace for 18 months. All the people taking part will have the same design of twinblock brace. You will be randomly allocated to two groups. The difference is when you have your treatment, group 1 means you have the brace straight away, group 2 means that you wait 18 months until you are a little older.

What are the possible benefits and risks of participating?The quality of your brace treatment is the same whether you enrol in study or not. Usually for the twinblock brace there is a waiting list of 18 months or longer. So if you are in the later treatment group there is no difference in the time you wait. You may be in the immediate treatment group and start your brace quicker. There are no side effects to the treatment except some mild discomfort that you normally have with the twinblock braces. Paracetamol or headache tablets will take away any tooth or jaw ache.

Where is the study run from? The study is run from Tameside Hospital NHS, Foundation Trust, Manchester UK, and this is the lead centre. There are two other hospitals taking part these are St Lukes Hospital Bradford UK and University Hospital of NorthStaffordshire UK.

When is the study starting and how long is it expected to run for? The study has started at the lead centre in December 2011. The duration of the trial is 6 years. When the additional two hospitals sites are recruiting it is expected that the recruitment will be completed by December 2014.

Additional identifiers

EudraCT number

ClinicalTrials.gov number

Protocol/serial number

Study information

Scientific title

A randomised controlled trial to compare the effect of a twinblock brace to correct a receding chin with a delayed treatment/control group

Acronym

C2C

Study hypothesis

There is no difference in the effectiveness of a twinblock functional appliance compared with an delayed treatment control in terms of: 1. Skeletal and dental improvement2. Self esteem, psycho-social impact of malocclusion and oral health quality of life

Ethics approval

Multicentre Research Ethics Committee (MREC); 11/NW/0312

Study design

Randomised controlled trial

Primary study design

Interventional

Secondary study design

Randomised controlled trial

Trial setting

Hospitals

Trial type

Treatment

Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet

Condition

Intervention

The intervention is an orthodontic brace used to correct the small lower jaw and prominent upper teeth which is called a 'twinblock'. This brace has been in use for over 30 years and is used widely on growing children between 10.5 and 15 years old.All children wear the brace for 18 months. The difference is when you have your treatment Group 1: wears the brace straight away Group 2: has to wait 18 months to become a little older